Loans - Summary of Allowance for Loan Losses by Portfolio Class and Category (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
	Jan. 01, 2020	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Allowance for Loan Losses [Roll Forward]
Balance	$ 43,288
Portfolio loans, net
Allowance for Loan Losses [Roll Forward]
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)	28,387
Provision for Loan, Lease, and Other Losses		$ 14,027		$ 54,113
Balance at December 31, 2019	43,288	110,270		43,288
Provision for credit losses	(1,680)	14,000	$ 1,800	54,100	$ 5,000
Charge-offs		(2,584)		(6,552)
Recoveries		1,557		5,714
Balance	69,995	123,270		123,270
Portfolio loans, net | Commercial and industrial
Allowance for Loan Losses [Roll Forward]
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)	6,494
Provision for Loan, Lease, and Other Losses		8,929		27,688
Balance at December 31, 2019	27,455	50,139		27,455
Provision for credit losses	0
Charge-offs		(2,006)		(5,372)
Recoveries		808		1,605
Balance	33,949	57,870		57,870
Portfolio loans, net | CRE - investor owned
Allowance for Loan Losses [Roll Forward]
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)	10,726
Provision for Loan, Lease, and Other Losses		4,869		10,692
Balance at December 31, 2019	5,935	25,019		5,935
Provision for credit losses	(5)
Charge-offs		(272)		(498)
Recoveries		55		2,821
Balance	16,656	29,671		29,671
Portfolio loans, net | CRE - owner occupied
Allowance for Loan Losses [Roll Forward]
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)	2,598
Provision for Loan, Lease, and Other Losses		(1,854)		1,740
Balance at December 31, 2019	4,873	11,088		4,873
Provision for credit losses	(57)
Charge-offs		(30)		(30)
Recoveries		268		348
Balance	7,414	9,472		9,472
Portfolio loans, net | Construction and land development
Allowance for Loan Losses [Roll Forward]
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)	5,183
Provision for Loan, Lease, and Other Losses		2,873		11,220
Balance at December 31, 2019	2,611	15,962		2,611
Provision for credit losses	(217)
Charge-offs		0		(31)
Recoveries		83		152
Balance	7,577	18,918		18,918
Portfolio loans, net | Residential real estate
Allowance for Loan Losses [Roll Forward]
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)	3,470
Provision for Loan, Lease, and Other Losses		(1,132)		1,623
Balance at December 31, 2019	1,280	6,333		1,280
Provision for credit losses	(1,401)
Charge-offs		(173)		(327)
Recoveries		303		686
Balance	3,349	5,331		5,331
Portfolio loans, net | Other
Allowance for Loan Losses [Roll Forward]
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)	(84)
Provision for Loan, Lease, and Other Losses		342		1,150
Balance at December 31, 2019	1,134	1,729		1,134
Provision for credit losses	0
Charge-offs		(103)		(294)
Recoveries		40		102
Balance	$ 1,050	$ 2,008		$ 2,008